| 摘要 |
A seal ring which contains a scaly graphite powder essentially alone as a filler, and comprises 2 to 35% by weight of the graphite powder and 65 to 98% by weight of a polytetrafluoroethylene powder, wherein the graphite powder has an interplanar spacing of 0.335 to 0.340 nm, as measured by the powder X-ray diffraction method, and a size of a crystallite of (004) face of at least 70 nm is provided. Since deformation and extrusion of the seal ring are kept small even under a high pressure, and the abrasion of the opposite material can be prevented even if it is made of a soft metal, it is possible to maintain a stable sealing effect for a longer period of time. In addition, since the seal ring has small sliding resistance, handling property, response of the sealing device and suitability for fitting to the device can be largely improved. Thus, the seal ring is suitable for the valve device of power steering of automobiles, automatic transmission or shock absorber.
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